How to create Composite Object?
You can't make objects of different types into a single object, but you can make a group of "siblings" (children of an Empty) and duplicate them all together. This method doesn't create instances but whole new objects: they will still be editable individually (at the cost of being all simultaneously in memory).


Add an Empty


Select all the objects and then Shift+Select the Empty. Do CtrlP and Set Parent to Object


Duplicate the bunch (ShiftD) and Move (or rotate, or scale) the new Empty. Indeed, the duplication is smart enough to transfer the "Parent" relation to the new Empty




You can select a group (for example if you need to delete it or duplicate further) by selecting the Empty, then doing Select > Select More/Less > Extend Child or just Shift]